Fuse



T. E. MURRAY, 1a., AND J. B. MURRAY. 7

FUSE.

APPLICATION FILED JAN. 31, 1921.

1,435,651 Patented Nov. 14, 1922;

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made of an arched sheet metal cap Patented Nov. 14, 1922.

UNITED STATES PATENT OFFICE.

THOMAS E. MURRAY, IR, AND JOSEPH B. MURRAY, OF BROOKLYN, NEW YORK.

FUSE.

Application filed January 31, 1921. Serial No. 441,314.

To all whom it may concern:

Be it known that we, THOMAS E. MURRAY, J r., and JOSEPH B. MURRAY, citizens of the United States, residing in Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Fuses, of which the following is a specification.

Our invention aims to provide an electric fuse and a casing therefor which can be cheaply manufactured and which has other advantages referred to in detail hereinafter.

Figs. 1 and 2 are respectively a. longitudinal section and an end view of a fuse enclosed in a metal case;

Figs. 3 and 4 are respectively a plan and a longitudinal section of the fuse separated from the case.

t The fuse proper comprises a strip 1 of fusible metal with forked ends 2 for attachment to terminals and with a contracted central portion 3. An envelope 5 of asbestos or other refractory insulating -material is extended over the fuse proper continuously between its terminals so as to cover the contracted portion 3 of the fusible metal. This covering of the point where the fuse melts through in use prevents arcing and the passage of current from the broken end of the fuse outward and for this reason permits the use of a metal casing which would otherwise be dangerous.

In Fig. 1 we have shown the casing as 5 with flat sides 6 adapted to be attache by one or more screws 7 to a metal plate or base 8. The base 8 carries an insulating block 8 of porcelain with square lugs 8 projecting down through holes in the base and carrying on their ends box-shaped copper terminals 9', formed with bent tongues 10, threaded for attachment by means of screws 1.1 to the terminals 2 of the fuse 1; the orcelain having the shape and passage ilustrated. Fuse casings of this general shape, with terminals 9 projecting from one side thereof are used to bridge a gap at the opposite end of which are socket terminals like that indicated in dotted lines 12, Fig. 2, making contact with the side faces of the fuse casing terminals 9. The combination of fuse and case is used also as a plug switch to be pulled out from its terminals when the line is to be broken. For convenient manipulation in this respect we prefer to add a handle 13 Welded or otherwise mounted on the top of the casing.

Removal of the screws 7 permits a ready opening of the case and facilitates the insertion of a new fuse. The fact that the case is easily opened in this way makes it possible to run the tongue 10 well up into the casing where it is beyond the danger of accidental contact with articles on the outside. Yet when the cap 5 is removed the connecting screws 11 are easily accessible.

This entire case may be cheaply stamped out of steel (except for the copper terminals). Ample space is left within it to prevent arcing from any part of the fuse to the case, and the covering of the fusible portion of the link serves to prevent such arcing and permit the use of a metal case without danger. All the metal parts of the casing (not including the copper terminals) should be dipped in asphaltum or similar insulating coatin for greater security.

The casing escribed may be of various other known or suitable desi s, and may be used with or without the llin of comminuted refractory material whic is some times provided.

Though we have described with great particularity of detail certain specific embodiments of our invention, yet it is not to be understood therefrom that the invention is restricted to the particular embodiments disclosed. Various modifications thereof in detail and in the arrangement of the parts may be made by those skilled in the art without departure from the invention as defined in the following claims.

lVhat we claim is:

l. A casing for a fuse strip having a portion covered by an envelope of refractory insulating material, said casing having a portion of sheet metal adapted to enclose the insulated portion of said strip and having a base and terminals extending from said base and adapted for connection to the terminals of the fuse strip at points within the casing.

2. A fuse comprising a fuse strip and a casing having an arched portion of sheet metal and a base and having terminals exand extending therefrom and connected to the terminals of the strip at points Within the casing.

In Witness whereof, we have hereunto signed our names.

THOMAS E. MURRAY, Ja, JOSEPH B. MURRAY. 

